Amy Winehouse - 23-10-2012 at 14:34
Hey guys I have a nooby question, but its simple. In a lot of literature I notice references to CO2 evolution, sometimes as an observation, but other
times as a critical condition. Is there an obvious indication of CO2 evolution, or quite simply, what should I be looking for? The only option I can
think of is having a hose outlet out of a flask neck into some liquid and poking holes in the end of a teflon tube and looking for bubbles. This is
difficult under a vacuum or when working under an argon environment though.
Am I missing something? What's the indication?
Vargouille - 23-10-2012 at 15:40
There are a few ways of testing if an off-gassing is CO2 or not. The easiest (I think, at least) is just gathering a bottle full of the gas and
putting a lit splint into it. If it goes out, it might be CO2. A better way of testing, though, as Faraday mentions in his lectures on the candle, is
to pass the gas through lime-water. The precipitation of CaCO3 is quite noticeable. This may be better suited to ruling out gasses. O2, for example,
would relight a glowing splint, and have no reaction with lime-water; N2 would put out the splint, but have no reaction with lime-water; and H2 may
well explode.
The lime-water test may be incorporated into an argon environment (perhaps vacuum as well) by use of a gas-washing bottle, or similar device, artfully
set up.